MemoryAvailable

gives the estimated number of bytes readily available for storing additional data in the current Wolfram Language kernel session.

Details

MemoryAvailable[] reports memory that is available for allocation by your operating system.
MemoryAvailable[] is affected by other processes running on your computer system.
Dynamic[MemoryAvailable[]] gives dynamic results for available memory.
On Mac, MemoryAvailable[] returns the sum of free and inactive memory.
On Windows, MemoryAvailable[] returns the available memory reported by the operating system.
On Linux, MemoryAvailable[] returns the MemAvailable parameter value of /proc/meminfo.

Memory available in the current kernel session:

Set up a dynamic display of available memory:

Measure memory available before and after a computation:

The difference in available memory is roughly accounted for by the structure created:

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